This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Dietary caloric restriction (CR) is the only intervention to reliably extend the lifespan of a variety of species, including worms, flies, fishes and rodents. Whether CR can also extend the human lifespan remains unknown. The National Institutes of Aging's Caloric Restriction Study maintains long-term colonies of nonhuman primates that are evaluated for many health parameters and markers of aging and provide the best available nonhuman primate model to address this question. As part of this unique resource, groups of rhesus monkeys, including young and old groups on 30% calorically restricted or ad libitum diets, were maintained at ONPRC for 4.5 years, and large groups are being followed throughout their lifespan at NIA. Because of its accessibility to noninvasive monitoring, the eye is an ideal organ to evaluate longitudinally whether CR can retard the occurrence of aging and age-related disease, and therefore we are conducting in-depth studies of ocular aging in these monkeys. Based on previous observations in rats, we hypothesize that CR will reduce oxidative stress and delay aging and age-related disease in the eye. The two major goals of our project are: 1) to determine whether CR retards the development of aging and age-related ocular diseases including macular degeneration, cataract, glaucoma and optic nerve atrophy;and 2) to correlate clinical observations with histopathological studies, using markers of age-related degeneration and oxidative stress. This research can provide new insights into the causes and possible treatment of human age-related ocular disorders.